⊙研究目的和背景承载高铁列车的无砟轨道需使用预制的、一定规格的轨道板铺设。这种轨道板的安装精度要求非常高,1 m范围内误差不能超过2 mm。一般说来,为了将一个物体从初始位置(对高铁轨道铺设,就是龙门吊放置的初始位置)精确放置到另外一个位置,有可能需要对物体作6个参数的调节,即要对x、y、z轴3个方向的位移和分别绕x、y、z轴的转动等6个自由度进行调节,这就是我要制作六自由度 ⊙Purpose and Background of Research The ballastless track bearing the high-speed train must be prefabricated and laid with a certain size of track plate. This kind of rail plate installation accuracy is very high, the error within 1 m can not exceed 2 mm. In general, in order to precisely place an object from its initial position (to the high-speed rail track, which is the initial position of the gantry crane) to another position, it may be necessary to adjust the object by six parameters, that is, x, y, z-axis displacement in three directions and respectively around the x, y, z-axis rotation of 6 degrees of freedom to adjust, and this is what I want to make six degrees of freedom